Teaching aid



FIG. 1 is a front view of a teaching aid broken away to indicate indeterminate length showing my new design;

FIG. 2 is a rear view broken away to indicate indeterminate length thereof;

FIG. 3 is a left side view broken away to indicate indeterminate length with the right side view being a mirror image thereof;

FIG. 4 is a top view of a teaching aid; and,

FIG. 5 is a bottom view thereof. 

The ornamental design for teaching aid, as shown and described. 